1. Field of the Invention
An object of the present invention is a system of communications between an electronic service center and a user by means of an interface. It is designed particularly for fields in which access to the interface is conditioned on the presence of an electronic microcircuit of the token, chip carrier, chip card or other type, that is temporarily and detachably or permanently inserted into the interface. This type of system is found for example with portable telephones that are kept available to users but must be barred to persons who have not inserted a corresponding circuit. It also pertains to all payment terminals making direct use of chip cards notably in order to bring about cash withdrawals from bank accounts.
2. Description of the Prior Art
The problem encountered with systems of this type is related to the definition of the interface. Indeed, at a given instant, the known requirements of safety and comfort of the transaction entail the implementation of procedures using the interface. These procedure are open-ended and constantly developing. The consequence or drawback thereof is that obsolete interfaces need to be changed as and when the system develops.
It is possible, nevertheless, to envisage the updating of the interface operation systems in a manner similar to that used to update operating systems in microcomputers. However, the drawback of this method is that several updating operations have to be carried out. Furthermore, the owner, or manager, of an interface is not its user, i.e. the person who possesses the authorizing electronic circuit in question. For example, for a terminal enabling payment by chip cards in a restaurant, the owner of the interface is the restaurant-owner while the user or payer is the bearer of the chip card. This is also the case with portable telephone systems, notably in the field of rented cars in which the portable telephone (and hence the interface) belong to a car rental firm (or to a telecommunications network utility company) and where the chip card or electronic circuit concerned belongs to the user. In this case, a difference in updating, from one interface to another, may make the use very complicated for a user.
There is a necessary gap between the wishes of the user whose interest lies in obtaining access, with his card, to the very latest improvements and the concerns of the interface manager who may be tempted, for reasons of cost, to limit the number of campaigns for updating the interfaces that he is managing.
A practical example of a need is the one felt in the field of portable telephones where the interface manager or else the owner of the electronic service center would like to be able to count down prepaid units in users' chip cards, somewhat as is done for public telephones. Now, in present-day portable telephone sets, the interfaces are not provided, in their operating system, with a set of instructions that enables this countdown or reverse counting operation. This will be the case at a later date. The problem to be resolved in this particular case, therefore, is that of carrying out a countdown in the chip card, with an interface that is not provided with means for this purpose, of the countdown pulses that would be sent by a telephone electronic service center. The difficulty of the problem can clearly be seen.
An object of the invention is to find a solution to this problem and to propose far greater flexibility of use of the interfaces or operating terminals. Several approaches may be envisaged. It is possible, notably, to define a "universal" mechanism that enables the terminals to be managed transparently from the electronic service center. For this purpose, it would be necessary to equip every existing terminal with this new mechanism. This approach is therefore an unrealistic one. The approach envisaged in the invention does not call for any modification of the terminal, and only uses resources of this terminal that are already available. These resources are either procedures available from the electronic service center or card instructions (these cards being fitted into the terminal) controlled from the electronic service center that enable data elements to be conveyed through the terminal up to the card. Furthermore, according to the invention, these terminals will themselves have the simplest possible operating system which, ultimately, will not even need to be constantly updated.
The idea of the invention entails the use, in the operating system of the interfaces, of a minimum set of instructions or even an existing procedure from the existing set of instructions. This set or this procedure is used to cause the designating, in a reserved zone of the memory of the chip, of an instruction of a complementary set, or extended set. This complementary instruction is then carried out either by the microprocessor of the chip card or by the microprocessor of the interface, these microprocessors acting on the designated peripherals. They prompt, for example, a display of information elements on a screen of the interface, a counting down of prepaid units in a memory of the chip card, a dispatching, to the electronic service center, of a report relating to the chip card and/or to the call in progress (notably for purposes of billing related to transmission times) or an invalidation of the chip card, etc.
With the existence of a reserved zone whose place and use are known, it is thus possible, with the minimum set of instructions of the interface operating system, to load the characteristics of an instruction. The characteristics of this instruction are either the instruction code of this instruction itself or an address of this instruction in a memory of the chip. In addition to this reserved zone, the microprocessor of the chip card contains an automatic process for carrying out the instruction whose characteristics have been loaded into the reserved zone. As soon as it is sought to increase the utilization capacity of a system, the characteristics of the instruction to be carried out are sent to the chip from the electronic service center. They are transmitted naturally by the interface. Since this interface is capable in practice of selecting and writing (this is a minimum) in a memory zone in the memory of the chip card, it can write the characteristics of this instruction therein. Subsequently, the microprocessor of the chip card takes over the operation in order to bring about the performance of this instruction with its automatic process.
In one improvement, rather than sending the instruction from the electronic service center, additional instructions will be loaded into updated chip cards, in additional sets of instructions. In this case, the characteristics of instructions to be sent by the electronic service center consist only of a designator, designating that one of the instructions which is to be carried out.
As a variant, an existing procedure is used to manage the card that is associated with the sending of a data element. A data element is given a particular form and, at reception in the card, it is ascertained that the data element has this particular form. If desired, an instruction of the extended set of instructions is carried out, and this instruction then corresponds to this particular data element.